The present disclosure relates to a common mode filter, and more particularly, to a common mode filter able to remove wideband noise.
In accordance with technological developments, electronic devices such as mobile phones, home appliances, personal computers (PCs), personal digital assistants (PDAs), liquid crystal displays (LCDs), and the like, have changed from being analog implemented to being digitally implemented, and electronic device speeds have increased due to an increase in an amount of data processed by the electronic devices.
Therefore, a universal serial bus (USB) 2.0, a USB 3.0, and a high-definition multimedia interface (HDMI) have widely been circulated as high speed signal transmitting interfaces, and have been used in many digital devices such as personal computers and digital high-definition televisions.
These high speed interfaces adopt a differential transmission system transmitting signals having a phase difference of 180 degrees using a pair of signal lines, unlike a single-end transmission system that has been generally used for a long period of time.
In a case in which phases of high frequency signals do not coincide with each other in the above-mentioned differential transmission, common mode noise occurs, and this noise is radiated, thereby influencing peripheral communications elements. As a coil component for filtering common mode noise, a common mode filter has been widely used. That is, common mode noise is noise generated in the differential signal line, and the common mode filter removes noises that may not be removed by an existing filter.
Therefore, the common mode filter may advantageously remove noise across a wideband. However, an existing common mode filter using two coils may merely remove noise of a natural frequency band designed according to a target value, and has a disadvantage in that it does not remove the noise across the wideband.